1. Field of the Invention
The field of the invention relates to methods and apparatus for removing gelatinous or other relatively soft tissue during a surgical procedure.
2. Brief Description of the Prior Art
The presence of certain types of soft tissue masses in the body often necessitates surgery. Lens tissue, which is generally a clear, transparent tissue located posterior to the pupil and iris, should be removed if it becomes opaque or milk-white in appearance. This condition is known as cataract, and can cause partial or total blindness.
A number of different techniques have been employed for removing cataractous tissue. U.S. Pat. No. 3,589,363 discloses a method for removing cataracts known as phacoemulsification. An ultrasonically vibrated tool is used in this method to break up the cataractous tissue. The tissue is then aspirated out of the eye by means of a suction device. An instrument for performing phacoemulsification is disclosed in U.S. Pat. No. 4,634,420. A small limbal incision, preferably three to four millimeters in length, is made into the anterior chamber of the eye if this instrument is employed.
Other types of cutting instruments are also known for performing surgery. U.S. Pat. No. 3,945,375 discloses an instrument for removing tissue which includes a fluted cutter drill housed in a probe. In use, the probe is inserted within an incision and the cutter drill caused to rotate with respect to the shearing edges of an opening in the probe. Suction is applied through the probe to draw tissue into the opening. A shearing cut is made between the cutter drill and the opening, and the tissue is removed through a passage within the probe.
Other types of surgical cutting instruments are disclosed in U.S. Pat. Nos. 3,732,858, 3,844,272, 3,937,222, 3,976,077, and 4,368,734.